The present invention relates generally to timing synchronization in communication systems and, more particularly, to timing synchronization for non-timing aware network nodes.
It is often advantageous in a communication network for devices in the network to have a common time base. For example, in 3G mobile/cellular communication systems, radio base stations (RBS) are synchronized to within a few microseconds. Precise synchronization facilitates efficient communication such as for allocation of time slots among devices and interference reduction. The electronics industry has developed several standard protocols for use in synchronizing clocks, for example, the Precision Time Protocol (PTP) of IEEE Std. 1588. PTP includes sending timing-related messages between nodes in a communication network. The timing-related messages include, for example, a first node transmitting over a link a time-stamped packet to supply its time base to a second node, and the second node transmitting, over the link, a packet to the first node requesting and thereafter receiving a reply with the time of receipt of the request packet, so that the second node may have information regarding packet time of travel over the link. With these timing related messages the second node may be able to synchronize its local clock to the clock time of the first node.
In many instances a network could have multiple nodes between nodes which are to be synchronized. Not surprisingly, a variety of constructs have been developed relating to timing distribution, and nodes may serve as or be identified as master clocks, boundary clocks, ordinary clocks (a category that may include master clocks), and transparent clocks, for example. The use of such constructs has been helpful in synchronizing nodes of larger networks.
Unfortunately, larger networks may also have many nodes which are not configured for PTP operations.